The present invention relates to a detection device, and particularly to a detection device for detecting excessive wear of a carbon brush of an autotransformer.
Conventional autotransformers consist of a single winding wound on a toroidal iron core and a shaft extends from a rotary arm with a carbon brush under the rotary arm for contacting with exposed turns of the transformer winding. However, as the rotary arm is frequently rotated by a hand of a user or a coaxial-coupled motor of a control system, the carbon brush will be worn out after a long-term utilization. Thus, an interconnection between the carbon brush and the winding is poor so that a sparking occurs at the autotransformer and a phase of a three-phase transformer may be disconnected. This results in fluctuation in an output voltage of the autotransformer and increases the possibility of burning down the apparatus connected to the autotransformer.